The Arduino is a popular microcontroller platform for getting stuff done quickly: it’s widely available, there’s a wealth of online resources, and it’s a ready-to-use prototyping platform. On the opposite end of the spectrum, if you want to enjoy programming every bit of the microcontroller’s flash ROM, you can start with an arbitrarily tight resource constraint and see how far you can push it.
[lucas][Radical Brad]’s demo that can output VGA and stereo audio on an eight-pin DIP microcontroller is a little bit more amazing than just blinking an LED.
[lucas][RB] is using an ATtiny85, the larger of the ATtiny series of microcontrollers. After connecting the required clock signal to the microcontroller to get the 25.175 Mhz signal required by VGA, he was left with only four pins to handle the four-colors and stereo audio. This is accomplished essentially by sending audio out at a time when the VGA monitor wouldn’t be expecting a signal (and [lucas][Rad Brad] does a great job explaining this process on his project page). He programmed the video core in assembly which helps to optimize the program, and only used passive components aside from the clock and the microcontroller.
Be sure to check out the video after the break to see how a processor with only 512 bytes of RAM can output an image that would require over 40 KB. It’s a true testament to how far you can push these processors if you’re determined. We’ve also seen these chips do over-the-air NTSC, bluetooth, and even Ethernet.
Continue reading “ATtiny Does 170×240 VGA With 8 Colors”
We always like seeing projects that salvage a classic piece of technology, and this one doesn’t disappoint. It’s a vintage kiosk- or console-style stereo, repurposed with every useful feature imaginable, but still made to look original. Until you open the lid, that is.
[Julian] has been hard at work on rebuilding this 1957 RCA stereo, and since he’s no stranger to these types of rebuilds, the results are pretty impressive. Underneath the hood is a 22″ touchscreen running Windows 7 and a Lepai amplifier. The controls for the stereo were placed towards the back, along with USB ports and an RJ45 connector for the computer.
The speakers in the stereo also needed to be replaced. For this, [Julian] used a set of Dayton speakers that worked well enough for this application. After mounting the speakers and all the other hardware in the unit, [Julian] noted that while it isn’t an audiophile’s dream stereo, it was nice to have all of these parts integrated together into something that looks nice. We’d have to agree!
There are a lot of rejuvenated antique stereos around too, like this Bluetooth-enabled tube amp radio, or this Soviet-era handheld, or even this slightly more modern stereo. There’s just something classy about having a vintage-looking thing spruced up with modern technology!
Way back in the previous century, people used to use magnetized strips of tape to play music. It might be hard to believe in today’s digital world, but these “cassette” tapes were once all the rage. [Steve] aka [pinter75] recently found a Bang & Olufsen stereo with this exact type of antequated audio playback device, and decided to upgrade it with something a little more modern.
Once the unit arrived from eBay and got an electronic tune-up, [pinter75] grabbed a Galaxy S3 out of his parts drawer and got to work installing it in the old cassette deck location. He used a laser cutter to make a faceplate for the phone so it could be easily installed (and removed if he decides to put the tape deck back in the future).
The next step was wiring up power and soldering the audio output directly to the AUX pins on the stereo. Once everything was buttoned up [pinter75] found that everything worked perfectly, and mounted the stereo prominently on his wall. It’s always great when equipment like this is upgraded and repaired rather than thrown out.
Riding around with headphones on is not the safest of things; those people
are trying to could hit you! [Victor Frost] was actually pulled over for doing it. Although the bicycle police didn’t ticket him, they did push him over the edge to pursuing a compromise that lets him listen to tunes and perhaps still hear the traffic around him.
The build puts 200 Watts of audio on his rear luggage rack. He used a couple of file totes as enclosures, bolting them in place and cutting one hole in each to receive the pair of speakers. The system is powered by two 6V sealed lead-acid batteries which are topped off by a trickle-charger when the bike is parked.
Looking through this log we almost clicked right past this one. It wasn’t immediately apparent that this is actually version four of the build, and these are completely different spins each time. The top-down view of plastic-tacklebox-wrapped-v3 is sure to make you grin. Video overviews of the first two versions are linked in [Victor’s] details section of the project page linked at the top of this post. The progress is admirable and fun time digging through. They’re all quite a bit different but bigger, better, and more self-contained with each iteration.
Okay, okay, maybe this isn’t going to shake the neighborhood… until he adds a Bass Cannon to it.
The PIC microcontrollers are powerful little devices, and [Tahmid] is certainly pushing the envelope of what these integrated circuits can do. He has built (for educational purposes, he notes) an audio player based on a PIC32 and a microSD card. Oh, and this microcontroller-based audio player can play in stereo, too.
The core of the project is a PIC32MX250F128B microcontroller. 16-bit 44.1kHz WAV files are stored on the microSD card and playback is an impressive 12-bit stereo audio. It can also play back 8-bit files (with some difficulty). [Tahmid] programmed the interface to work through the serial port and it is very minimalistic, mostly because this was a project for him to explore audio on a microcontroller and wasn’t to build an actual stand-alone audio player that he would use from day to day.
Still, even though the project isn’t ready to replace your iPod, the core audio-processing parts are already done if you want to try to build on [Tahmid]’s extensive work. You could even build a standalone audio player like this but have it play high-quality 12-bit stereo audio!
Continue reading “Stereo Audio on a PIC32”
If you are looking for a way to spice up your summertime parties, try following [Pastryboy’s] lead. After letting the idea rattle around in his head for a few years, he finally built himself the cooler he always dreamed of.
[Pastryboy] was originally inspired by a YouTube video he found a few years ago. He took the basic concept and rolled with it. He started out with a mini fridge he found for $10. He removed the compressor and other plumbing bits. He also removed all of the internal shelving. Any leftover holes were patched up with silicone. Now when the fridge is laid on its back, it’s essentially the same as an ordinary cooler.
Next [Pastryboy] purchased two 6.5″ Boss speakers and an inexpensive head unit. He drilled a few pilot holes in the side of the refrigerator and then used a jigsaw to cut the holes to the proper sizes. Once the speakers were mounted in place, he needed to find a way to waterproof the inside. This was accomplished by using some small plastic bowls. The edges of the bowls were attached to the cooler wall using silicone.
[Pastryboy] was able to run most of the cabling through the inside of the cooler’s walls. The system is powered by a 12V lead acid battery. He chose a specific model of battery that can be stored in any orientation and that can handle being knocked around a little bit.
Next he added a couple of handles to the sides to make it easier to transport. A small bit of ski rope was attached to the inside of the lid, preventing the lid from flopping completely open. [Pastryboy] also added a drain to the bottom to make it easier for one person to empty the cooler. The final touch was to pretty it up a bit. He sanded down the entire thing and gave it several coats of red paint. The end result looks very slick.
Most of the work that [Ron] has done in the past with vacuum tubes and solid state electronics has been repair. At 59 years old, he finally put together his own stereo tube amplifier and we have to admit it definitely has an awesome look.
The platform is built around the well-known 6V6 beam-power tetrodes which are mostly used by major audio brands for their guitar amplifiers nowadays. The Dynaco 6V6 circuit based PCB was bought from China and minor changes were made to it. The amplifier uses one transformer to convert the US 120VAC into 240VAC and 9VAC, the first being rectified by a glassware PS-14 power supply while the later is converted regulated at 6.3V for the tube heaters. The output stage consists of two Edcor audio transformers (one for each channel) that converts the high voltage for its 8 ohms speakers. The home-made chassis provides proper grounding and as a result you can’t hear any background noise.
We are very curious to know if some our readers have been experimenting with glass tubes for audio applications. Please let us know your experience in the comments section below.